feat(app): update PWA icons to ✦ star design and fix chat panel default

Replace chat-bubble PWA icons with the four-pointed star (✦) used in
the interface. Fix panelSide default so chat appears on the left and
content surface on the right. Add CLAUDE.md project guide and
.claude/launch.json dev server config.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.claude/launch.json

@@ -0,0 +1,19 @@
+{
+  "version": "0.0.1",
+  "configurations": [
+    {
+      "name": "app",
+      "runtimeExecutable": "pnpm",
+      "runtimeArgs": ["--filter", "@aiui/app", "dev:vite"],
+      "port": 5173,
+      "autoPort": true
+    },
+    {
+      "name": "claude-proxy",
+      "runtimeExecutable": "pnpm",
+      "runtimeArgs": ["--filter", "@aiui/app", "dev:proxy"],
+      "port": 3141,
+      "autoPort": true
+    }
+  ]
+}